Applifier, which helps games get discovered on Facebook, has launched a new mobile discovery bar to make it easier for social games to spread on mobile devices. The bar is part of a cross-promotion network.

Applifier chief exec Jussi Laakkonen told VentureBeat that the mobile tool will let users view a recommended game from high-profile spots such as the opening screen of a mobile game. If the user taps on the bar (pictured at the bottom of the above screen), they get more information on a game. Or they can slide the bar to see other games on offer. Applifier is trying to solve one of the toughest problems for mobile games: getting discovered in an ocean of apps for mobile platforms. We’ve done two conferences on the topic and it continues to be a burning issue in mobile gaming circles.

Applifier launched in April, 2010 on Facebook in the form of a bar (pictured above) that advertised a bunch of games from Applifiers partners. If a user clicked on the bar, he or she could start playing that game right away. Now there are more than 150 million monthly active users and 800 games in the Applifier network. The cross promotions have driven more than 100 million game installations. Applifier originally referred to its partners as the “rebel alliance,” after the good guys in the Star Wars movies, who were competing against the dominant social game company Zynga, which can easily cross-promote its own games on its Zynga bar.

Laakkonen said the free Applifier bar has helped hundreds of Facebook publishers grow faster, since they don’t have to spend their profits on as much pure promotion.

But what works on Facebook won’t necessarily work on mobile, according to Laakkonen and other speakers on the Mobile Game Discovery panel at our GamesBeat 2011 conference earlier this week. As you can see from the images, there is a lot more room to promote games on Facebook than there is in a mobile game.

Still, Laakkonen hopes that similar tactics will work on mobile. Applifier is today launching on iPhone, iPad, and iPod. Support for Android devices will begin in the third quarter. Typically, the main way games get noticed on Apple’s App Store is when Apple features a game in its prime spotlight. Another way is to make it to the top 25 lists.

The cross-promotion bar is non-incentivized. That is, it doesn’t offer the user an incentive, or bribe, to install the advertised app. That will keep Applifier in good graces with Apple, which recently banned pay-per-install incentivized apps. The promotion is effective because it reaches people who are already interested in playing new games.

“Our value proposition for the players is simple: Hey, you like games. How about some more?” said Laakkonen, who recently moved Applifier from Helsinki, Finland, to San Francisco.

Pekka Kuuasema, CEO of mobile game maker Kuuasema, said Applifier has done a great job coming up with its mobile app and that his company will participate in the program. Right now, the new mobile Applifier is in an invitation-only beta test.

Applifier’s backers include MHS Capital, PROfounders Capital, Tekes, Lifeline Ventures and angel investors.